(1) Field of the Invention:
This invention relates to a novel photochromic compound and to a photochromic composition, which comprises the photochromic compound, useful as a variety of recording materials or photochromic materials.
(2) Description of the Related Art:
A variety of photochromic organic compounds have heretofore been known. Of these, spirooxazine compounds are known as those having relatively good repeatability of color-developing function, namely, durability of the color-developing function. 1,3,3-Trimethylspiro[indoline-2,3'-(3H)-naphtho(2,1-b)(1,4)oxazine] and derivatives thereof are disclosed in, for example, Japanese Patent Publication No. 28892/1970, Japanese Patent Publication No. 48631/1974, Japanese Patent Laid-Open No. 36284/1980, Japenese Patent Laid-Open No. 53586/1985, Japanese Patent Laid-Open No. 53288/1986 and Japanese Patent Laid-Open No. 263982/1981.
Photochromic compounds consisting of the conventional respective spirooxazine compounds however involve a problem that they do not exhibit enough photochromism at room temperature or above room temperature.